To report a case of idiopathic orbital inflammation presenting as unilateral acute dacryoadenitis in a child.

A nine-year-old boy presented with painful swelling and redness in the right upper eyelid and temporal conjunctiva without systemic symptoms for five days. Acute orbital cellulitis was suspected but did not respond to systemic antibiotics. An orbital computed tomogram and magnetic resonance imaging revealed a diffusely enlarged and inflamed right lacrimal gland. The patient showed dramatic response to systemic corticosteroids, and acute dacryoadenitis due to idiopathic orbital inflammation was diagnosed. Treatment with oral corticosteroids for two months resolved the inflammation. No relapse was observed during four months of follow-up.

Although rare, acute dacryoadenitis as a localized nonspecific orbital inflammation should be considered in the differential diagnosis of acute orbital cellulitis in pediatric patients.